Hypervalent Iodine Mediated Chemoselective Iodination of Alkynes

Reported herein are practical approaches for the cherhoselective mono-, di-, and, tri-iodination of alkynes based on efficient oxidative iodinations catalyzed by hypervalent iodine reagents. The reaction: conditions were systematically optimized by altering the iodine source and/or the hypervalent iodine reagent syStem; The tetrabutylammonium iodide (TBAI)/ (diacetoxyiodo)benzene (PIDA) system is specific for monoiodination, while the KI/PIDA system results in di-iodination. Combining the TBAI/PIDA and KI/PIDA systems in one provided the:corresponding tri-iodination products efficiently. These reaction conditions can be applied to the synthetically important iodination of aromatic and aliphatic alkynes, which was accomplished in good yield (up to 99%) and excellent chemoselectivity. These synthetic methods can also be applied to the efficient chemoselective synthesis of iodoalkyne derivatives, interthediates, and related biologically active compounds.